1. Field of Invention
The present invention relates generally to space launch vehicles that use rocket engines to move payloads from the surface of the Earth to a desired orbit or trajectory. The present invention is also useful in the art of suborbital sounding rockets. More specifically, the present invention is a launch apparatus that utilizes a space frame truss structure to transfer propulsive loads to the payload and to simultaneously distribute vibration loads over the truss structure of the space frame of the launch vehicle and to further distribute these vibration loads to the space frame's truss structure's connecting nodes.
Another purpose of the present invention is to provide a space launch apparatus whose load bearing members form a triangular pyramid whose structural geometry distribute force applied to any part of its structure throughout its entire structure and all of its structural members and connecting nodes to allow the apparatus to withstand loads caused by resonance between the vibration spectra produced by operation of its rocket engines and the resonant frequencies of its structure.
The present invention also has the purpose of providing a space launch apparatus that has a plurality of modular space frame truss structures that can be prefabricated, moved to the launch site as a kit of parts and then the majority of the space launch apparatus can be assembled at the launch site from these parts.
Yet a further purpose of the present invention is to provide a launch apparatus whose structural integrity is maintained by a space frame comprised of truss structures whose elements include a plurality of compression members and tension members including tension members that are flexible cables, whereby said space frame is structurally robust, inexpensive to manufacture and easy to construct.
2. Background
All currently operating space launch apparatus use rocket motors as reaction engines that create thrust by expelling mass. Chemical rockets create thrust by reacting propellants within a combustion chamber pressure vessel to produce hot gas at high pressure. This hot gas is accelerated by being compressed passing through a venturi and then expanding through a bell or aerospike nozzle. Space Launch apparatus' are usually multistage and have a diameter to height ratio of greater than 1 to 10. These multi stage apparatus' sometimes fail due to vibration and accelerated loads acting on their structure; especially they are susceptible to failure at the separation planes between stages of vehicle in a multistage vehicle. An example of such a space launch apparatus is the Saturn five rocket built by NASA for the Apollo program. The Saturn five has a height to width aspect ratio of approximately 1 to 10. It is the largest rocket ever flown being about 110 m long and about 10 m in diameter. All space launch vehicles share the Saturn five's geometric form, i.e. a plurality of relatively skinny cylinders stacked on top of each other. A multistage rocket comprising a plurality of stacked cylinders must balance all of the rocket stage cylinders on top of each other during its operation. The interface planes between these rocket stages must withstand the vehicle's vibration and acceleration loads without structural failure. Complex coupled loads analysis is required to verify that these interfaces between the rocket stages and between the rocket stages and the payload are capable of withstanding the heavy vibration and acceleration loads. This analysis is a critical part of the flight qualification. For large multistage launch vehicles carrying heavy payloads, these mechanical loads must be managed with great precision for the rocket to operate without failure. Put simply, current launch vehicles are very delicate structures.
In the 1960s and 1970s American aerospace companies proposed to design and construct much larger launch vehicles. Because the inventor cannot build and test a working model of the present invention, some information about these carefully engineered large vehicles should be useful as background to show that the present invention is technically credible and reasonable.
Chrysler's single stage earth orbital reusable vehicle (SERV); a NASA 1971 phase A space shuttle study, proposed a rocket that was 96 feet wide and the 101 feet tall to carry over 50 tons to low Earth orbit (LEO) using a single reusable rocket stage. SERV proposed to use this aspect ratio of height to diameter because it returned from orbit like a gigantic Apollo capsule. SERV was proposed to be powered by a 32 Mega Newton aerospike rocket motor. A ground test version of part of this rocket engine was designed, built and ground tested by the Rocketdyne Corporation. The entire SERV was to launch, fly to orbit, release its payload and then reenter the atmosphere like an Apollo capsule and land vertically using turbojet engines. [Final report of NASA Contract NAS8-26341]
Aerojet Corporation proposed the Sea Dragon; a 1963 design study for a fully reusable two-stage rocket that would launch 508 metric tons to low earth orbit. This rocket was 150 m long by 23 m in diameter. It would have been built at a shipyard and then towed out to sea to be launched. Launching from the ocean was considered beneficial because it requires fewer support systems. The rocket was to be made of 8 mm steel sheeting. Aerojet technically validated all aspects of the Sea Dragon proposal including conducting multiple trial launches of smaller rockets from the ocean. These ocean test launches were not conducted from ships. The rocket was to be submerged in the ocean and launched from the water. The Sea Dragon was designed by Robert Truax, who also designed the US Navy's Polaris missile to be fired from a submerged nuclear submarine. Aerojet concluded that a sea launch could reduce the launch site costs by up to 95%. The Sea Dragon vehicle had two stages. The first stage was to be powered by a single 360 Mega Newton rocket motor burning RP-1 and liquid oxygen at 17 atm pressure. This engine was pressure fed. For comparison, the space shuttle's liquid fueled main engine cluster produces 5.7 Mega Newton of thrust. The most powerful liquid fueled engine ever built, the Russian RD-170, produces 7.9 Mega Newton of thrust and the solid rocket boosters used by the American space shuttle, which are the largest solid fuel rockets yet built, produce 14 Mega Newton of thrust each. [Final Report, NASA contract NAS8-2599 summary]